A key element of the Union’s plan to win the Civil War was General-in-Chief Winfield Scott’s “Anaconda Plan.” James McPherson describes General Scott’s idea in his classic account of the war, Battle Cry of Freedom:
Instead of invading the South, Scott proposed to “envelop” it with a blockade by sea and a fleet of gunboats supported by soldiers along the Mississippi. Thus sealed off from the world, the rebels would suffocate and the government “could bring them to terms with less bloodshed than by any other plan.”
The Anaconda Plan was of course not successful, as General Scott had hoped, in avoiding a hot war. Indeed the conflict turned out to be the bloodiest in the nation’s history in terms of American lives lost. And historians have disputed ever since over how much the plan actually contributed to the Confederacy’s eventual destruction.
But the strategy of blockading Confederate ports also raised a sticky legal conundrum that implicated the legal status of the rebel states and potentially undermined the very premise on which the Union was fighting the war: had the secession by the confederate states from United States been constitutional in the first place?
The Prize Cases
In choking off access to Confederate ports, President Lincoln had two options; the Union could “close” southern ports or it could “blockade” them. “Closing” ports implied that the Union considered the rebel states to still be part of the United States, but engaged in an insurrection. Conversely “blockading” ports was an act of war under international law, and doing so would necessarily recognize the Confederacy as a belligerent nation, and thus that the rebel states had indeed exited the Union.
The blockade option could encourage Britain and France to remain neutral, because under the law of admiralty, neutral ships were entitled to travel freely between neutral ports without being harassed, whereas ships supporting belligerent nations could be taken as “prizes.” Professor White explains:
Traditionally, when in a wartime setting American ships captured vessels allegedly containing “enemy” property, the seized ships were brought into U.S. ports and identified as potential prizes, that is, lawful captures in war. Judicial determinations of the status of the captured ships were then held in federal courts. If a court ruled that the ships were lawful prizes, they could be confiscated and their cargoes sold at public auction. At prize adjudications, owners of ships tried to show that the ships, or their cargoes, were the property of friendly or neutral nations rather than belligerents.
Keeping Britain and France from coming in on the side of the Confederacy was one of Lincoln’s major war aims, but deprived of southern cotton, they had a strong incentive to do so. Blockade might provide a potential counter-incentive for them to remain neutral to protect their shipping in the Atlantic. Conversely, British and French ships caught transporting goods to and from closed southern ports would be smugglers subject to criminal prosecution under U.S. law, threatening to exacerbate tensions with those countries when Lincoln wanted to make nice.
But blockade was not a great option for a couple of reasons. For one thing, if the Union blockaded southern ports, it might actually give European nations an excuse to recognize the Confederacy as a sovereign nation, the very outcome Lincoln was trying to avoid. More fundamentally, though, the Union rejected the entire premise that secession was permitted by the Constitution, and so it could not recognize the Confederacy as an independent sovereign on which it could wage war. Lincoln himself had said in his inaugural address that “no State upon its own mere motion can lawfully get out of the Union,” and that “in view of the Constitution and the laws the Union is unbroken.”
And if the Confederacy were a belligerent nation, the Union would have to respect its sovereign rights under international law once the Union finally triumphed in the war. But if the federal government had simply put down an internal insurrection, instead of defeating a foreign nation in a war, it could reoccupy the southern states without having to bother with the niceties of international law.
When Britain declared neutrality, Lincoln went with the blockade option. But at the same time, he did not ask Congress for a declaration of war and continued to treat the conflict as an internal matter he could address under his independent constitutional authority to suppress insurrections. When in the summer of 1861, prize cases resulting from the blockade started percolating up through the courts, the federal government was met with the legal conundrum it had created, as Professor White describes:
In those cases, the owners of ships or cargo seized as allegedly lawful prizes argued, in effect, that the U.S. government could not have it both ways. Since the U.S. government declined to recognize the Confederacy as an independent sovereign, they maintained, it could not treat the Confederate states as belligerents under the laws of war. And since Congress had not declared war on the Confederacy, Lincoln had no authority to issue the blockade, and no ship could be treated as a prize for violating it.
But as it turns out, when the Prize Cases arrived at the Supreme Court in 1863, a bare majority of justices was willing to let the federal government have its cake and eat it too after all. The majority opinion by Justice Grier disputed the premise that nations can only make war on other nations, holding that “it is not necessary to constitute a war, that both parties should be acknowledged as independent nations or sovereign States.” The Civil War was both a “war” and an “insurrection,” meaning that the federal government could blockade southern ports without recognizing the Confederacy as a sovereign nation and the booties taken enforcing the blockade were legit prizes.1
Might and right
By winning the war, the Union conclusively resolved the fate of the Confederacy and eventually restored the rebel states to the Union, but victory on the battlefield did not answer the underlying legal question: had secession been constitutional in the first place? Southerners continued to assert a “compact” theory of sovereignty, according to which the states had voluntarily agreed to join the Union but retained the right to leave whenever they saw fit. That they had lost the war did not mean they had been wrong to secede; the Union’s victory was merely a case of might makes right. After all, intra armes silent leges.2
Some responded that the war had amounted to a trial by combat, which confirmed the righteousness of the Union cause. According to medieval legal theory, trial by combat revealed who should win a legal dispute because God would ensure the meritorious party won the fight. But trial by combat died out in the dark ages because bludgeoning your opponent into submission doesn’t really establish the soundness of your legal position.
Concerns over the constitutional merits of secession even delayed the much anticipated treason trial of Jefferson Davis, which sputtered and eventually petered out with a whimper. Although prosecutors brought an indictment, they sat on the case until it was eventually mooted when President Andrew Johnson issued a general amnesty in the late 1860s. Prosecutors had worried that a jury might conclude that secession is constitutional, in which case the ex-confederates had only exercised their constitutional rights and were not traitors at all.
The war was over, but the constitutional logic of secession continued to haunt Reconstruction. The question was deeply troubling. In the south, unreconstructed ex-confederates clung to the supposed legitimacy of the lost cause. Meanwhile, northerners asked themselves, if secession was valid, what had they all fought and died for?
The legal uncertainty of waging war on non and quasi state actors has continued to vex the U.S. government.
In times of war, the law falls silent